Gold Nanobones Enhanced Ultrasensitive Surface-Enhanced Raman Scattering Aptasensor for Detecting Escherichia coli O157:H7.

Sensitive, robust, and highly specific detection of Escherichia coli O157:H7, one of the most hazardous foodborne pathogens and the cause of numerous diseases, is needed to ensure public health. Herein, a one-pot step method is reported for the preparation of multifunctional gold nanobones (NBs) (GNRApt-1+RhB) from gold nanorods (GNRs) comediated by an aptamer (Apt-1) and the signal molecule rhodamine B (RhB) for surface-enhanced Raman scattering detection of E. coli O157:H7. The characterized result showed that Apt-1 and RhB were embedded in the gold NBs, and then, this combination exhibited good recognition, excellent stability, and significant Raman signal intensity enhancement. The Raman enhancement derived from a strong electromagnetic field distribution with the locations at the apex of both ends of the GNRApt-1+RhB and the signal stability was because of the firm embedment of Apt-1 (poly A20 + E. coli O157:H7 aptamers) and RhB on the surface of the GNRApt-1+RhB. Optimization experiments established that surface-enhanced Raman-scattered RhB absorption at 1350 cm-1 had a strong linear relationship (y = 180.30x - 61.49; R2 = 0.9982) with E. coli O157:H7 concentration over the range of 10-10,000 cfu/mL with a limit of detection of 3 cfu/mL. This novel aptasensor sensitively detects E. coli O157:H7 and has great promise for food pathogenic bacteria detection.